Several types of Flexible Containment Structures including Flexible Intermediate Bulk Containers (FIBCs), Flexible Enclosures, Flexible Transfer Sleeves, Flexible Glove Bags and Flexible Isolators are used in the containment and processing of particulate material. These devices are used to contain the particulate materials during the development through production and transfer operations when producing toxic powder products. The purpose is to prevent exposure of the toxic powder to workers and to prevent contamination of the particulate material from the exterior environment. The Flexible Containment Structures are connected to processing equipment; they contain process equipment and connect to storage devices including metal drums, fiber drums and intermediate bulk containers. There are several types of mechanical docking interfaces that are integral to the processing equipment or attached to the processing equipment that accommodate the attachment of these Flexible Containment Structures. These include Multiple O-Ring Canisters, straight walled rigid tubes, rigid rings, tubes and rings that have a raised feature at one end or tubes and rings that have feature along the exterior wall and also pan bases for open bottom enclosure applications.
Connections to mechanical docking interfaces of the process equipment are accomplished by pulling a tube of thin film over the mechanical docking interface and applying a compression member to the exterior film surface to complete a seal between the film and the mechanical docking interface surface. The purpose is to make a good seal between the Flexible Containment Structure and the mechanical docking interface. Compression member designs include bungee cord, O-Ring, rubber band, adhesive tape, mechanical clamp, wire tie or other similar device.
A short coming of this type of connection is that it does not completely seal the thin film to the mechanical docking interface. Small wrinkles are induced in the Flexible Containment Structure/mechanical docking interface connection when installed. The cause of the wrinkles is that the film diameter of the Flexible Containment Structure connection is larger than the processing equipment it is attached to so that the nearly inelastic film structure can be easily pulled over the mechanical docking interface. The goal is to join nearly inextensible materials to rigid components and create a leak tight seal. When the compression member is applied to the exterior of the Flexible Containment Structure the diameter of the Flexible Containment Structure is reduced, small wrinkles form resulting in a number of channels between the inside Flexible Containment Structure surface and the mechanical docking interface surface. These channels are areas where small particles of powder or contaminates can migrate through creating a breach in containment.
Examples of such connections can be found in: System for the Contained Transfer of Particulates U.S. Pat. No. 6,653,377; Method of the Contained Transfer of Particulates EP 1 721 829 B1, Method of the Contained Transfer of Particulates EP 1 728 717 B1